I am not sure if the mzR warning you get is the problem (I will still commit a fix to get rid of it later today). The (or one) issue, however, is clearly there is no package called 'MetShot'. I tried installing devtools::install_github("sneumann/MetShot"), which worked on my computer.

Could you load, or if not available, install the following dependencies and start again: CAMERA, xcms, XML, class and Biobase.